Display unit structure for electronic device

ABSTRACT

A display unit structure for an electronic device is formed of a solar cell, and a display unit. The display unit includes a transparent base layer disposed on the solar cell, and a hologram layer laminated on the base layer and having a virtual mirror plane for reflecting a light with a predetermined wavelength. The virtual mirror plane of the hologram layer is inclined with respect to front and back surfaces of the hologram layer. Thus, the light with the predetermined wavelength is reflected by the hologram layer, and light other that the predetermined wavelength is transmitted to the solar cell.

FIELD OF THE INVENTION

This invention relates to a display unit structure for an electronicdevice having a display unit which reflects a light having apredetermined wavelength and transmits lights other than the lighthaving the predetermined wavelength.

DESCRIPTION OF THE BACKGROUND ART

Recently, a solar battery has been significantly improved intechnologies and been widely used for various electronic devices as thelight source for electronic watches, electronic calculators, portableradios, and the like.

As such a solar battery, an amorphous solar battery produced by applyingamorphous silicon to a glass substrate or a metal substrate is generallyused.

There is a case of using a solar battery of this type in a display unitstructure for an electronic watch as shown in FIGS. 9 and 10.

As shown in FIGS. 9 and 10, this display unit has a structure in whichfour solar cells 2 of a planar fan shape are disposed in parallel on theperiphery and over a movement 1, and are electrically connected inseries an insulating band 3 is interposed between the solar cells 2, atransparent plane 4 formed from a polycarbonate or acryl resin islaminated on the insulating band 3 and solar cells 2, and a commercialname, characters 5 for displaying time, and the like are displayed onthe transparent plane 4 by printing or the like. Incidentally, it isimportant that electronic watches provided with the display unitstructure of this type not only have excellent functions but alsoexhibit an excellent appearance.

However, in conventional display unit structures for electronic watches,the solar cells 2 have a dark brown or dark blue color so that the watchdisplay is viewed as if it has a dark brown or dark blue color. Also,since the insulating band 3 is interposed between the solar cells 2, itis viewed as a material with a planar cross shape. There are substantiallimitations to the design including the color tone of the watches andthe product quality is also degraded.

There is a display unit structure for an electronic device disclosed inJapanese Patent Publication No. 38464/1993 to solve the above problems.

This display unit structure for an electronic device comprises a solarbattery for supplying power to a movement for driving a device, a colorfilter capable of transmitting a light of a wavelength contributing topower generation of the solar battery, and a scattering layer made of awhite scattering plate which transmits part of the light from the colorfilter and scatters the remainder in all directions.

Here, the scattering layer is, for example, made of an acrylic opaqueplate, produced by applying a delustering clear lacquer on a halfmirror, or produced by roughing one of the surfaces, the other surfacebeing laminated with aluminum to form a mirror.

However, in these display unit structures for electronic devices, theformer scattering layer is seen as a darkish white because it mustpartially transmit light, whereby, for example, a metallic color whichexhibits a high-class appearance cannot be provided. On the other hand,in the latter scattering layer, the light transmission varies and acolor shade occurs due to uneven layer thickness. As a result, thedisplay unit cannot be provided with the desired color tone, causing theproblem that the degree of freedom in designing the appearancedecreases.

In addition, in the conventional display unit structures for electronicdevices a light having a predetermined wavelength is scattered in alldirections. When an observer views a display unit, the scattered lightcan be viewed not only from a specific direction along the usual line ofsight but also from all the directions. The transmittable lighttransferred to a solar battery is reduced and hence the utilizationefficiency of the light is reduced.

Accordingly, the present invention has been achieved in view of thissituation and has an object of providing a display unit structure inwhich a display device includes a hologram layer provided with a virtualmirror plane for reflecting a light having a predetermined wavelengthand the virtual mirror plane of the hologram layer is located in aposition which allows the virtual mirror plane of the hologram layer tobe inclined to the front and back surfaces of the hologram layer,thereby improving the degree of freedom in designing the appearance andalso improving the light utilization factor.

DISCLOSURE OF THE INVENTION

The above object can be attained in the present invention by theprovision of a display unit structure for an electronic devicecomprising a display unit including a hologram layer provided with avirtual mirror plane for reflecting a light having a predeterminedwavelength, with the virtual mirror plane of the hologram layer locatedin a position which allows the virtual mirror plane of the hologramlayer to be inclined to the front and back surfaces of the hologramlayer.

By these measures, when an observer arranges the line of sight on thepath of the light having a predetermined wavelength reflected on thevirtual mirror plane of the hologram layer, the light having thepredetermined wavelength reaches the observer, whereas lights ofwavelengths other than the specific length penetrates the hologramlayer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a vertical sectional view of a main portion of an internalmechanism of a wrist watch provided with a display unit structure for anelectronic device corresponding to a first embodiment, in which theinternal structure of the movement and the like are omitted.

FIG. 2 is a vertical sectional view of the display unit structure of theelectronic device corresponding to the first embodiment.

FIG. 3 is a vertical sectional view for explaining incident lights,reflecting lights, and transmitting lights relating to the display unitstructure for the electronic device corresponding to the firstembodiment.

FIG. 4 is a vertical sectional view of a main portion of an internalmechanism of a wrist watch provided with a display unit structure forthe electronic device corresponding to a second embodiment, in which theinternal structure of the movement and the like are omitted.

FIG. 5 is a vertical sectional view showing the case where a watch withelectro luminescence illumination is incorporated in a display unitstructure for the electronic device corresponding to a third embodiment,in which the internal structure of the movement and the like areomitted.

FIG. 6 is a vertical sectional view showing the case where ananalogously indicative watch is incorporated in a display unit structurefor the electronic device corresponding to a fourth embodiment, in whichthe internal structure of the movement and the like are omitted.

FIG. 7 is a vertical sectional view showing a display unit structure forthe electronic device corresponding to a fifth embodiment, in which theinternal structure of the movement and the like are omitted.

FIG. 8 is a vertical sectional view showing a display unit structure forthe electronic device corresponding to a sixth embodiment, in which theinternal structure of the movement and the like are omitted.

FIG. 9 is a top plan view of a main portion of a wrist watch providedwith a conventional display unit structure for an electronic device.

FIG. 10 is a vertical sectional view of a conventional display unitstructure for an electronic device.

DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS

The present invention will now be explained in detail.

FIG. 1 is a vertical sectional view of a main portion of an internalmechanism of a wrist watch provided with a display unit structure forthe electronic device corresponding to a first embodiment, FIG. 2 is avertical sectional view of the display unit structure for the electronicdevice corresponding to the first embodiment, and FIG. 3 is a verticalsectional view for explaining incident lights, reflecting lights, andtransmitting lights relating to the display unit structure for theelectronic device corresponding to the first embodiment.

In these figures, the symbol 11 represents a case band/case body made ofa metal or a synthetic resin, which is formed entirely from acylindrical material with both ends open. An internal flange 12 havingflange ends 12a, 12b and projecting in the radial direction of the caseband/case body is integrated with the internal peripheral surface closeto one of the openings (the upper opening in the Figures) of the caseband/case body 11.

The symbol 13 represents a glass made of glass or a synthetic resin andformed entirely from a transparent material of a circular shape insection. The glass 13 is installed inside the openings of the caseband/case body so that its periphery is connected to the flange end 12a.

The symbol 14 represents a case back made of a metal or a syntheticresin. The case back 14 is made of a non-transparent material and has alid body 14a facing the other of the openings (the lower opening in theFigures) of the case band/case body 11 and an engaging part 14b facingthe inside of the other opening of the case band/case body 11. The caseback 14 is installed in the other opening of the case band/case body 11via a case back packing 10.

The symbol 15 represents a movement for rotating the hands. The movement15 consists of a step motor 15a, a decelerating train wheel (not shown),and the like and is held in the case band/case body 11 via a casingring/casing frame 16.

The symbol 17 represents a hand display unit for analogously indicatingtime. The hand display unit 17 includes a minute hand 18 and an hourhand 19 which are a hour hand and a minute hand respectively. The handdisplay unit 17 also includes a center wheel & pinion 20 and an hourwheel & pinion 21 which are respectively drive shafts for the minutehand 18 and the hour hand 19. The hands 18, 19 are rotated by drivingthe movement 15 to indicate time variably.

The symbol 22 represents a solar cell for supplying power to the stepmotor 15a for driving the movement. This solar cell 22 comprises a metalplate 22c formed of an SUS material or the like and an amorphous siliconlayer 22b formed on the metal plate 22c by vapor deposition or the like.The solar cell 22 is disposed between the flange end 12b of the insideflange 12 and the movement 15 and is connected to the movement 15through a circuit substrate 23. In the center of the solar cell 22, ashaft insertion hole 22a is provided by opening both upward and downward (in the axial direction of the wheels & pinions 20, 21). Electricpower generated in the solar cell is stored in a secondary battery or ina condenser (neither are shown) for a while.

The symbol 24 represents a display mechanism including the hand displayunit 17. The display mechanism 24 also includes a transmission-typereflecting plate 25 and a coating layer 26 and disposed at the sideopposite to the movement on the solar cell 22.

The transmission-type reflecting plate 25 is composed of a base layer 27provided with a shaft insertion hole 27a communicating with the shaftinsertion hole 22a in the center thereof and a hologram layer 28provided with a shaft insertion hole 28a communicating with the shaftinsertion hole 27a of the base layer 27. The transmission-typereflecting plate 25 is disposed at the side of the solar cell on theinner flange 12.

The base layer 27 is placed at the side opposite to the movement on thesolar cell 22 and is formed entirely from a transparent material made ofa synthetic resin such as polyester or polyethylene terephthalate. Bythese structures, the incorporation of the transmission-type reflectingplate 25 into the display mechanism 24 and the handling of the solarcell 22 can be simply performed.

The hologram layer 28 is formed of a volume type hologram (Lippman typehologram) and is laminated on the base layer 27 at the side of thehands. This hologram layer 28 is positioned at an inclination withrespect to the surface 28b and back face 28c of the hologram layer.Also, the hologram layer 28 includes a virtual mirror plane 29 which, asshown in FIG. 3, receives incident lights a and reflects only a light b1having a predetermined wavelength in a specific direction.

Specifically, the hologram layer 28 has characteristics dependent on thewavelength and on the angle of reflection. Because of this, among theincident lights a from a light source 31, only the light b1 having apredetermined wavelength is reflected on the virtual mirror plane 29 ina specific direction which never coincides with the directions of thepaths of surface reflecting lights b2 and b3 which are each shown as adotted line in FIG. 3 and reach an observer 32. Also, the hologram layer28 has light transmittability and hence, as the solid line shown in FIG.3, a light b4 of the wavelength other than the wavelength b1 penetratesthe transmission-type reflecting plate 25 and reaches the solar cell 22.

On the other hand, the coating layer 26 is provided with a shaftinsertion hole 26a communicating with the shaft insertion hole 28a andis, as shown in FIGS. 2 and 3, attached to the hologram layer 28 at thehands side via an adhering layer 33. The coating layer 26 is formedentirely from a transparent or translucent material of a synthetic resinsuch as polycarbonate, acrylate, polyester, or the like. The lightresistance and moisture resistance of the hologram layer 28 areincreased and also the incorporation of the transmission-type reflectingplate 25 into the display mechanism 24 can be simply performed. Anauxiliary display unit 34 (shown in FIG. 1) including characters,patterns, marks, and the like, which constitutes a display unit otherthan the hand display unit 17 is formed on the hand side of the coatinglayer.

In addition, the wheels & pinions 20, 21 are inserted into each shaftinsertion hole for the coating layer 26, hologram layer 28, solar cell22, and circuit substrate 23.

In such a display unit structure for an electronic device, when theincident light a from the light source 31 penetrates the coating layer26 and enters into the hologram layer 28, the light b1 having apredetermined wavelength is reflected on the virtual mirror plane 29. Atthis time, if the observer 32 arranges the line of sight on the path ofthe light b1 having a predetermined wavelength, the light b1 having thepredetermined wavelength reaches the observer 32 and is viewed as thelight of a specific color.

Here, when the observer 32 alters a sight point or the position of awatch, thereby to disarrange the line of sight on the path of the lightb1, the light b1 never reaches the observer 32.

Accordingly, the solar cell 22 can be shielded so that it is not viewedfrom the hands side and also a desired color tone for the display unit(transmission-type reflecting plate 25) can be obtained, whereby thedegree of freedom in designing the appearance can be increased.

On the other hand, the light b4 of a wavelength other than thewavelength b1 penetrates the hologram layer 28 and base layer 27,reaches the solar cell 22, and is utilized for power generation of thesolar cell 22. The generated power is supplied to the movement 15 via acondenser (not shown) to drive the movement 15 and thereby to rotate thewheels & pinions 20, 21.

Therefore, the incident light which enters the hologram layer 28 neverscatters in all directions to result in an increase in the lightentering the hologram layer 28, whereby the light utilization efficiencycan be promoted.

In addition, the observer 32 arranges the line of sight in the direction(the path of lights b1) which allows the hand display unit 17 to beviewed so that the time can be read.

Next, a second embodiment will be illustrated with reference to thedrawing.

FIG. 4 is a vertical sectional view of a main portion of the internalmechanism of a wrist watch provided with a display unit structure for anelectronic device corresponding to a second embodiment, in which thesame or equivalent materials as those in FIG. 1 are represented by thesame symbols (excluding the solar cell). Therefore detailed descriptionsare omitted and, also, in FIG. 4, the internal structure of the movementand the like are omitted.

In FIG. 4, a solar cell represented by the symbol 41 is similar to thesolar cell 22 in the first embodiment and includes a metal plate 42formed of a SUS material or the like and of an amorphous silicon layer43 formed on the metal plate 42 by vapor deposition or the like. Thesolar cell 41 is supported in a case band/case body 11 via a casingring/casing frame 16. An electrode 41a connecting with a terminal 23a ofa circuit substrate 23 via a compressed coil spring 44 is formed in thesolar cell 41.

In such a display unit structure for an electronic device, when theincident light a from the light source 31 enters a transmission-typereflecting plate 25 (hologram layer), a light b1 is reflected on thevirtual mirror plane 29 and a light b4 of the wavelength other than awavelength b1 penetrates the transmission-type reflecting plate 25 andreaches the solar cell 41. Therefore, a degree of freedom in designingthe appearance can be increased in the same manner as in the firstembodiment.

Next, a third embodiment will be described with reference to thedrawing.

FIG. 5 is a vertical sectional view showing the case where a watch withelectro luminescence illumination incorporated in a display unitstructure for an electronic device corresponding to a third embodiment,in which the same or equivalent materials as those in FIGS. 1 and 2 arerepresented by the same symbols, so that detailed descriptions areomitted. Also, in FIG. 5, the internal structure of the movement and thelike are omitted.

In FIG. 5, the symbol 51 represents an electro luminescence panel.Wheels & pinions 20, 21 (shown in FIG. 1) are inserted into the centerof the electro luminescence panel 51 which is disposed between amovement 15 and a transmission-type reflecting plate 25. The electroluminescence panel 51 includes upper and lower circular transparentsections 52, 53 made of a synthetic resin, which face each other at aspecific interval in a vertical direction (the axial direction of thewheels & pinions 20, 21), inner and outer cylindrical seal materials 54,55, which extend inner and outer peripheries of the transparentmaterials 52, 53 respectively, and a fluorescent body 56 of zinc sulfateor the like which is imposed between both of the sealing materials 54,55 and both of the transparent sections 52, 53. The electro luminescencepanel 51 emits light by the application of an a.c. voltage, whereby ahand display unit 17 is illuminated.

In such a display unit structure for an electronic device, the electroluminescence panel 51 can be shielded so that it is not viewed from thehands side. Also a desired color tone for the display unit(transmission-type reflecting plate 25) can be obtained, whereby thedegree of freedom in designing the appearance can be increased.

Next, a fourth embodiment will be described with reference to thedrawing.

FIG. 6 is a vertical sectional view showing the case where ananalogously indicating watch is incorporated with a display unitstructure for an electronic device corresponding to a fourth embodiment,in which the same or equivalent materials as those in FIGS. 1 and 2 arerepresented by the same symbols, so that detailed descriptions areomitted. Also, in FIG. 6, the internal structure of the movement and thelike are omitted.

In FIG. 6, the symbol 61 represents a metal plate including a shaftinsertion hole 61a into which wheels & pinions 20, 21 are inserted. Themetal plate 61 is disposed between a movement 15 and a transmission-typereflecting plate 25.

Also, different from the embodiments shown in FIG. 1 and 5 an auxiliarydisplay unit 62 including characters, patterns, marks, and the like isintegrally formed with and over the entire surface of a coating layer26.

In such a display unit structure for an electronic device, the internalstructure of a watch can be shielded so that it is not viewed from thehands side. Also, a desired color tone for the display unit(transmission-type reflecting plate 25) can be obtained, whereby thedegree of freedom in designing the appearance can be increased.

Next, a fifth embodiment will be described with reference to thedrawing.

FIG. 7 is a vertical sectional view showing a display unit structure foran electronic device corresponding to a fifth embodiment, in which thesame or equivalent materials as those in FIG. 6 are represented by thesame symbols, so that the detailed descriptions are omitted.

In FIG. 7, the symbol 71 represents a coating layer which constitutes apart of a display mechanism 24. The coating layer 71 is provided with ashaft insertion hole 71a communicating with a shaft insertion hole 28aand is attached to a hologram layer 28 at the hands side via an adheringlayer 33. The coating layer 71 is formed of the same transparentmaterial as the coating layer 26 in the first embodiment or of atranslucent material. A circular wall 71b covering the outer peripheryof a transparent reflecting plate 25 is integrated with the outerperiphery of the coating layer 71 at the side opposite to the hands(below in FIG. 7). The light resistance and moisture resistance of ahologram layer 28 are further increased.

In such a display unit structure for an electronic device, a metal plate61 and the like can be shielded so that it is not viewed from theoutside. Also, a desired color tone for the display unit(transmission-type reflecting plate 25) can be obtained, whereby thedegree of freedom in designing the appearance can be increased.

Incidentally, though the case where the virtual mirror plane 29 issingle is shown in each embodiment, a plurality of virtual mirror planesis provided in general as shown in FIG. 8 (sixth embodiment). When theobserver 32 arranges the line of sight on the path of the light b1having a predetermined wavelength reflected on the virtual mirror plane29, the light b1 having a predetermined wavelength can be viewed as alight of a specific color.

INDUSTRIAL APPLICABILITY OF THE INVENTION

As is clear from the above illustrations, the display unit structure foran electronic device corresponding to the present invention can be usedfor display unit structures for various electronic devices such aselectronic watches, electronic calculators, portable radios, and thelike.

What is claimed is:
 1. A display unit structure for an electronicdevice, comprising:a solar cell, and a display unit including atransparent base layer disposed on the solar cell, and a hologram layerlaminated on the base layer and having a virtual mirror plane forreflecting a light with a predetermined wavelength, said virtual mirrorplane of the hologram layer being inclined with respect to front andback surfaces of the hologram layer so that the light with thepredetermined wavelength is reflected by the hologram layer and lightother than the predetermined wavelength is transmitted to the solar cellthrough the hologram layer.
 2. The display unit structure for anelectronic device according to claim 1, wherein a coating layer made ofa synthetic resin is disposed on the front surface of the hologramlayer.
 3. The display unit structure for an electronic device accordingto claim 1, wherein the coating layer is made of a synthetic resinselected from a group consisting of a polycarbonate resin, acryl resin,and polyester resin.
 4. The display unit structure for an electronicdevice according to claim 1, wherein patterns, marks, and characters areformed on the coating layer.
 5. The display unit structure for anelectronic device according to claim 1, wherein the coating layer ismade of a colored translucent material.
 6. The display unit structurefor an electronic device according to claim 1, further comprising amovement, on which said solar cell is disposed, said movement having astep motor and shafts for hands, said solar cell and display unit havingshaft insertion holes for allowing the shafts to pass therethrough.
 7. Adisplay unit structure for an electronic device, comprising:a movement,an electro luminescent element formed at one side of the movement, and adisplay unit including a transparent base layer disposed on the electroluminescent element, and a hologram layer laminated on the base layerand having a virtual mirror plane for reflecting a light with apredetermined wavelength, said virtual mirror plane of the hologramlayer being inclined with respect to front and back surfaces of thehologram layer so that the light with the predetermined wavelength isreflected by the hologram layer and light other than the predeterminedwavelength is transmitted through the hologram layer.
 8. The displayunit structure for an electronic device according to claim 7, whereinsaid movement includes a step motor and shafts for hands, said electroluminescent element and display unit having shaft insertion holes forallowing the shafts to pass therethrough.
 9. The display unit structurefor an electronic device according to claim 7, wherein the display unitis a hand display unit.
 10. The display unit structure for an electronicdevice according to claim 7, wherein a side wall covering a side endsurface of the hologram layer is installed at an edge portion of thecoating layer.